Drive apparatus for cables

ABSTRACT

A cable drive for load bearing cables having a drive disc with a keyed groove which serves as a running groove and coacts with pairs of jaw-type clamps which are drawn into the groove by the cable tension. The clamps include a recess for gripping the cable, and are mounted on a further endless cable which serves as a hinge for the clamped pairs.

United States Patent l l l H Inventor Appl. No.

Filed Patented Assignee Priority Willi Gumlich Marktoberdorf, 'Allgau, Germany 3,730

Jan. 19, 1970 Dec. 21, 197 l Schlang & Reichart Maschinenlabrik Marktoberdorl, Germany Jun. 22, 1969 Germany DRIVE APPARATUS FOR CABLES 11 Claims, 5 Drawing Figs.

US. Cl 74/233024 Int. Cl F16h 55/36 Field of Search 74/23024 References Cited UNITED STATES PATENTS Berger Watts Gross Karlik Sherwin Primary Examiner-C. J. Husar Attorney-Allison C. Collard ABSTRACT: A cable drive for load bearing cables having a drive disc with a keyed groove which serves as a running groove and coacts with pairs of jaw-type clamps which are drawn into the groove by the cable tension. The clamps include a recess for gripping the cable, and are mounted on a further endless cable which serves as a hinge for the clamped pairs.

PATENIED M821 Ian SHEET 2 [1F 2 F ig.5

INVENTOR WILLI GUMLICH ATTORNEY DRIVE APPARATUS FOR CABLES This invention relates to a cable drive for cables. More specifically, this invention relates to a cable drive, wherein the driving disc for the cables is provided with a key groove which serves as a runner groove. The key groove coacts with a pair of jaw clamps which are drawn into the key groove under the influence of the cable tension. This causes the cable to be clamped. The cable jaw clamps are further provided with recesses which correspond to the cable diameter. Means are provide for opening the clamps as soon as the cable leaves the jaw clamps. This construction results in reducing undue wear and tear on the cable, a feature which is of particular advantage for cables with one or two strands. In endless cable drives, the load is often unevenly distributed so that cables of a rather small diameter are subject to unusual wear and tear, a disadvantage having a detrimental effect on the cable reels.

A device as described above is illustrated in German Pat. No. 416,051. The trunnion of each pair of clamps is guided in radially positioned grooves in the rim of the drive pulley. Between the inner ends of the clamp arms of each pair ofjaw clamps is disposed a pressure spring, positioned to open the clamps when the cable leaves the clamps.

When the clamps are opened, the clamp arms pull the clamps outwardly. The arms for the clamps engage the flat inclined portion of the groove for the cable.

The application of this conventional cable drive is limited to very large cable drive discs, such as for example, in elevators. The guide of each pair of clamps which is trunnioned in radially directed grooves of the disc rim is subjected to strong wear and tear in its circumferential direction, which in turn, can lead to static overloading and abnormal wear and tear. The pair of jaw clamps are, therefore, installed to facilitate easy replacement. Moreover, the maximum pull-in power of the cables in the radial direction is limited. Therefore, the full effectiveness of clamping the working or loaded cable becomes questionable. In other words, the total device is of questionable operational value. Cable drives for elevators have to be absolutely safe and are subject to stringent safety regulations to avoid accidents. However, the above-described device does not fulfill safety regulations in any way.

The present invention provides a cable drive of the aforementioned type which is improved over the known devices and which is substantially unlimited in its application. This device is also applicable for a driving disc of relatively small diameter and is relatively inexpensive in its construction, and is free of static loads.

In accordance with the invention, a pair ofjaw clamps are mounted in series on a cable which serves as a hinge link cable for all clamps. The band of clamps is larger than the circumference of the drive disc and encompasses the drive pulley together with the working or loaded cable. In the closed position, the pair of clamps receives the working or loaded cables and form a key-shaped grooved profile in the running groove of the drive disc. The inventive device assures an effective power transmission between the running groove of the driving disc and the jaw clamps.

The jaw clamp band encompasses the cable diameter to a large extent and assures that the cable will maintain its shape. In the driving disc, only a simple key groove serves as a running groove. The jaw clamp band may be composed of a series of even jaw clamp links. The extension of thejaw clamp band over the driving disc circumference serves to open the jaw clamps at the time the cable leaves the jaw clamps. This creates a free area of the jaw clamp band and acts as a return loop. In that loop, the carrying cable can be pulled out of the jaw clamp band. The jaws are thus opened, and can be maintained open by means of centrifugal and/or magnetic forces until the carrying cable reenters the device. The invention preferably uses rigid guides along the free lengths of the jaw clamp band, so that the band cannot be twisted or swiveled around its associated hinge cable.

ln an advantageous and preferred embodiment of the invention, it is suggested that the jaw clamp band encompass a further keyed groove disc which opens the jaw clamps due to the relatively wide key groove angle in the disc.

In a further embodiment of the invention, the jaw clamps are provided with two hinge loops and two associated openings provided in the opposite hinge loops and engaged by the opposite hinge loops.

In still a further embodiment of the invention, the hinge loops are provided with upper and lower edges respectively. Limit stops are also provided for limiting the maximum opening of the jaws of the clamps. In the present invention, one embodiment is used in which short pairs ofjaw clamps are positioned in series in the longitudinal direction of the cable, except in the portion which includes the locking link for the hinge cable.

It is therefore an object according to the present invention to provide a cable drive apparatus having a plurality of hinged jaw-type clamps which selectively engage and disengage a load bearing cable.

It is another object according to the present invention to provide a cable drive apparatus which is simple in design, easy to manufacture, and reliable in operation.

Other objects and features of the present invention will become apparent from the following detailed description considered in connection with accompanying drawings which disclose the embodiments of the invention. It is to be understood, however, that the drawings are designed for the purpose of illustration only, and not as a definition of the limits of the in vention.

In the drawings, wherein similar reference characters denote similar elements throughout the: several views:

FIG. 1 is a plan view of a device ofthe present invention;

FIG. 2 shows onejaw clamp,

FIG. 3 shows a pair ofjaw clamps within the driving disc;

FIG. 4 shows one pair of clamps within the cable pulley; and

FIG. 5 is a cross-sectional view of locking link between jaw clamps.

Referring to FIGS. 1-5, there is shown a driving disc 2 with a drive mounted on baseplate l. A keyed grooved running groove 2 is provided on the drive disc and is encompassed over more than half of its circumference by a belt consisting of a plurality of pairs ofjaw clamps 8 which are mounted in series with respect to each other. The belt also encompasses a cable pulley 6 which is mounted pivotally about a trunnion 5 on a rocker bar or swinging arm 4. The swinging arm 4 is pivoted around an axle pinion 3 mounted on baseplate l, and is urged upward by a tension spring 7, which provides the necessary tension to the belt for thejaw clamps.

In order to drive cable 20, each jaw clamp 8 is provided with an enlarged radial recess 8' and also comprises two hinge loops or teeth 9 and corresponding openings 9' which are arranged opposite hinge loops 9 for engagement with hinge loops 9. The hinge link is formed by an endless cable 10 on which all pairs ofjaw clamps are mounted. At the point where the endless cable is joined together, a cable clamp is provided at b in FIGS. 1 and 5 and a pair ofjaw clamps are missing. It should be noted that the free space b is used to thread in cable 20. The upper edge 9" of the hinge loops 9 close the bottom of recess 8. Upper edge 9" and lower edge 9" limit the maximum opening for the jaws on the outside of driving disc 2 and cable pulley 6 as can be seen in FIG. 4.. A pivotable arm I2 is pivotable around axis 11 which is mounted on baseplate I. A press roller 14 which is pivoted on pin 13 on arm 12 is urged by means of tension spring 15 to press a passing jaw clamp 8 into the keyed running groove 2, which is provided on driving disc 2v This operation assures that a frictional clamp force on cable 20 is maintained over a portion of disc 2 which is independent of the load which is exerted on the cable. These friction forces are not released even if a sudden load is exerted on the cable, but do change into sliding friction forces. When a load is exerted on the jaw clamps, the cable is drawn into the keyed running groove 2', so that an increasing portion is encompassed up to the point where the cable engages driving disc 2. The clamping pressure between running groove 2' and the pair of jaw clamps 8 is created in the zone of the encompassing recess 8' which drives the cable 20, as can be seen in FIG. 3. Hinge loops 9 do not fill up keyed groove 2' in spite of the fact that hinge loops 9 engage the sides of the keyed groove profile of running groove 2. Since the hinge link is in the form of an endless cable 10, it does not form a positive connection with the opening of the hinge link, provided that the opening has a larger diameter when in the clamped direction rather than rectangularly thereto, and provided that the cable diameter is smaller than the diameter of the opening, and finally that the cable is compressible in its diameter. Therefore, an actual key groove clamping is achieved in the zone of recess 8, whereby the oppositely arranged pair of jaw clamps move parallel with respect to each other, while the are being drawn into the running key groove 2.

At the same time, recess 8 encompasses cable 20 which is driven almost around the total disc circumference. The described keyed groove clamp between jaws 8 and running groove 2 of driving disc 2 assures a high power transmission with less encompassing of driving disc 2 by cable 20. This also keeps the diameter of the driving disc 2 as small as possible,

even when heavy loads are exerted. The shortness of .the encompassing protects cable 20. If the direction of movement of the device is reversed, that is, opposite to the direction indicated by arrow L in FIG. 1, then a second pressure roller 14 can be provided on the opposite side of driving disc 2.

In order to be able to move cable 20 in and out of recesses 8' of the jaw clamps, it is necessary for jaw clamps 8 to open after leaving driving disc 2. The jaw clamps are opened when cable 20 is drawn into running groove 6' of a cable pulley 6. The keyed groove of running groove 6' is wider on the outside and smaller on the inside (FIG. 4) with respect to running groove 2 of driving disc 2. The open keyed groove profile edges of hinge loops 9, as shown in FIG. 3, are pressed together as it enters into groove 6' of cable pulley 6. This causes the jaws to open outwardly around hinge link 10 by releasing cable 20, as shown in FIG. 4.

Cable 20 can then be discharged over return roller 19. Pulley 6 and grooves 6 also permit cable 20 to be smoothly introduced between the pairs of jaw clamps 8 while they are in an open position, after cable 20 returns around the axis 16 of return roller 18. In order that cable 20 be completely enclosed in recess 8, the upper edges 9" of the hinge loops 9 form a closed bottom. Cable pulley 6 is guided between return pulley l8 and driving disc 2 in such a manner that cable 20 is subjected to a slight downward movement in the direction of the bottom of recess 8' when the cable is engaging cable pulley 6.

A guide for the pairs of jaw clamps 8 is formed between driving disc 2 and cable pulley 6 by means of hinge link cable 10 and cable 20. This guide is only missing during the assembly of this device. Rigid guide bars on a cover shield 21 keep the unsupported or free portion of the jaw clamps 8 from excessively swiveling around hinge link cable 10, and also assist cable 10 to correctly engage the running groove. The guide bars are so arranged that they do not contact the jaw clamps during the operation of the device.

While only a few embodiments of the present invention have been shown and described, it will be understood that many changes and modifications may be made thereto without departing from the spirit and scope of the invention.

What is claimed is:

l. A cable drive apparatus for driving a load-bearing cable, comprising;

at least one drive disc having a keyed circumferential groove,

an endless flexible cable disposed around said disc and having a length which is longer than the circumference of said drive disc,

a plurality of pairs of jaw-type clamps hingedly mounted in series on said endless cable and disposed in said drive disc for selectively gripping the load-bearing cable, and

a second disc having a widened keyed groove for opening said jaw clamps to release the loading cable. 2. The cable drive apparatus as recited in claim 1 further comprising rigid guides disposed between said first and second discs for sliding contact over the free portion of said endless cable.

3. The cable drive apparatus in accordance with claim 1 additionally comprising rigid guides for sliding contact over the free portion of said endless clamp.

4. The cable drive apparatus in accordance with claim I wherein said pairs of jaw clamps include hinge teeth and corresponding openings for the hinge teeth.

5. The cable drive apparatus in accordance with claim 4 wherein said hinge teeth include upper and lower edges which serve to limit the maximum opening said clamp jaws.

6. The cable drive apparatus in accordance with claim I wherein short pairs of said jaw-type clamps are mounted in series with respect to each other and extend to the joined ends of said endless cable.

7. A cable drive apparatus for driving a load-bearing cable, comprising;

at least one drive disc having a keyed circumferential groove, an endless cable disposed around said drive disc and having a length longer than the circumference ofsaid drive disc,

a plurality of pairs of jaw-type clamps hingedly mounted in series substantially adjacent to each other on said endless cable so as to form an endless clamp, said cable serving as a hinge link for all pairs of said jaw clamps, said jaw clamps being provided with recesses which substantially encompass the diameter of said load cable and receive and grip said load-bearing cable when said jaw clamps are urged into said keyed groove in said drive disc as a result of tension placed on the load-bearing cable, and

means for opening said jaw clamps when said clamps leave said keyed groove in said drive disc so as to allow said load-bearing cable to be released by said jaw clamps.

8. The cable drive apparatus as recited in claim 7 further comprising a second disc pivotably mounted on said driving apparatus for tensioning said endless cable, and wherein said means for opening saidjaw clamp comprises a widened keyed groove disposed in said second disc for opening said jaw clamps to release the loaded cable.

9. The cable drive apparatus as recited in claim 7, wherein short pairs of said jaw-type clamps are mounted in series with respect to each other and extend to the joined ends of said endless cable.

10, The cable drive apparatus as recited in claim 7, wherein said pairs of jaw clamps included hinged teeth consisting of upper and lower edges which serve to limit the maximum opening of said clamp jaws, and corresponding openings for said hinged teeth.

11. The cable drive apparatus as recited in claim 7 further comprising rigid guides disposed between said first and second discs for sliding contact over the free portion of said endless clamp. 

1. A cable drive apparatus for driving a load-bearing cable, comprising; at least one drive disc having a keyed circumferential groove, an endless flexible cable disposed around said disc and having a length which is longer than the circumference of said drive disc, a plurality of pairs of jaw-type clamps hingedly mounted in series on said endless cable and disposed in said drive disc for selectively gripping the load-bearing cable, and a second disc having a widened keyed groove for opening said jaw clamps to release the loading cable.
 2. The cable drive apparatus as recited in claim 1 further comprising rigid guides disposed between said first and second discs for sliding contact over the free portion of said endless cable.
 3. The cable drive apparatus in accordance with claim 1 additionally comprising rigid guides for sliding contact over the free portion of said endless clamp.
 4. The cable drive apparatus in accordance with claim 1 wherein said pairs of jaw clamps include hinge teeth and corresponding openings for the hinge teeth.
 5. The cable drive apparatus in accordance with claim 4 wherein said hinge teeth include upper and lower edges which serve to limit the maximum opening said clamp jaws.
 6. The cable drive apparatus in accordance with claim 1 wherein short pairs of said jaw-type clamps are mounted in series with respect to each other and extend to the joined ends of said endless cable.
 7. A cable drive apparatus for driving a load-bearing cable, comprising; at least one drive disc having a keyed circumferential groove, an endless cable disposed around said drive disc and having a length longer than the circumference of said drive disc, a plurality of pairs of jaw-type clamps hingedly mounted in series substantially adjacent to each other on said endless cable so as to form an endless clamp, said cable serving as a hinge link for all pairs of said jaw clamps, said jaw clamps being provided with recesses which substantially encompass the diameter of said load cable and receive and grip said load-bearing cable when said jaw clamps are urged into said keyed groove in said drive disc as a result of tension placed on the load-bearing cable, and means for opening said jaw clamps when said clamps leave said keyed groove in said drive disc so as to allow said load-bearing cable to be released by said jaw clamps.
 8. The cable drive apparatus as recited in claim 7 further comprising a second disc pivotably mounted on said driving apparatus for tensioning said endless cable, and wherein said means for opening said jaw clamp comprises a widened keyed groove disposed in said second disc for opening said jaw clamps to release the loaded cable.
 9. The cable drive apparatus as recited in claim 7, wherein short pairs of said jaw-type clamps are mounted in series with respect to each other and extend to tHe joined ends of said endless cable.
 10. The cable drive apparatus as recited in claim 7, wherein said pairs of jaw clamps included hinged teeth consisting of upper and lower edges which serve to limit the maximum opening of said clamp jaws, and corresponding openings for said hinged teeth.
 11. The cable drive apparatus as recited in claim 7 further comprising rigid guides disposed between said first and second discs for sliding contact over the free portion of said endless clamp. 